The use of certain block copolymers and their compounds in a number of end-uses and especially in footwear, is rapidly expanding. For example, in the footwear industry, certain block copolymer compounds are being used in large volume in the manufacture of a wide variety of shoes including canvas shoes, sport shoes, and dress shoes. The block copolymers may be utilized for this purpose for soling, foxing, innersoles and the like. These compositions are disclosed in Hendricks et al, U.S. Pat. No. Re. 28,236. In general, these shoe component compositions usually comprise a mixture of block copolymer, extending oil, polystyrene and possibly a filler. Many other end-uses of block copolymers are known, such as in pharmaceutical applications, sportswear and other artifacts. For the most part, these block copolymers have proved to be particularly advantageous in many respects, including flexibility, processability, lack of vulcanization requirement and wet slip. However, in certain respects, short-comings have been noted. With respect to footwear, one of the major short-comings of the block copolymer compounds such as those referred to in U.S. Pat. No. Re. 28,236 is the phenomenon known as "elephant hide". Moreover, these prior art compounds are often difficult to remove from molds and are prone to exhibit surface markings.
The term "elephant hide" refers to a problem primarily apparent in relatively thick sections of stock, whether it be soling, heavy sheeting or the like. The phenomenon is readily apparent when the compound, deficient in the respect, is flexed. During the flex, the compressed surface of such articles exhibits a ridged appearance. A new composition has been found that greatly reduces the elephant hide characteristics of the finished shoe soles.